<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
<style>

    ul{
        list-style: none;
    }
a{
        display: block;
        width: 123px;
        background-color: #0078D7;
        text-decoration: none;
        line-height: 30px;
        color:#fff;
        border-left:#002050  10px solid;
        text-align: center;
        margin-bottom:  1px;


    }
    a:hover{
        background-color: #002050;
        border-left: #0078D7 10px solid;
    }
</style>

</head>
<body>

    <ul>
        <li ><a href="#">返回首页</a></li>
    
        <li><a href="#">课堂概要</a></li>
    
        <li><a href="#">教学单元</a></li>
    
        <li><a href="#">教学资料</a></li>
    
        <li><a href="#">互动课堂</a></li>
    
         <li><a href="#">台联系我们</a></li>
    </ul>
</div>


</body>
</html>